Depot Fuzz problems

[Andyisdumb]

I just finished building the Depot Fuzz, it passes signal, but when I turn it on it just feeds back with no guitar signal, the treble knob acts as a volume, and the voice control changes the pitch of the feedback (which I suppose makes sense) I’m totally lost on how to fix this issue, what would be causing this?

 

[carlinb17]

Can you supply some clear images of both sides of the board, power, jacks, and switch

 

[Andyisdumb]

I hope these help!

 

[fig]

Is R11 47kΩ? It appears to be a 470kΩ…may just be me…

Nope, I had the wrong order…

 

[Andyisdumb]

Is R11 47kΩ? It appears to be a 470kΩ…may just be me…

Nope, I had the wrong order…

Are you sure? I may need to double check this

 

[fig]

The 2N3904 may be backwards.

 

[fig]

 

[fig]

Nope, it’s correct as well.

 

[Andyisdumb]

View attachment 30402

Wouldn’t it not make any sound of it was? Also it’s printed on the board (E,B,C) I looked at this exact picture before I started soldering haha

 

[fig]

Sorry, my eyes/brain were not cooperating at all last night apparently

IF me, I would reflow after double-checking the values. If I still had issues, I’d audio probe starting at the input pad of the pcb.

 

[Coda]

Is anything grounding out against anything else? Bit of exposed wire, solder tit, something like that?…

 

[carlinb17]

could the amount of flux still on the board be causing an issue?

 

[Andyisdumb]

could the amount of flux still on the board be causing an issue?

I’m not sure, I just built the amentum boost a week ago and I thought for sure I ruined it for this reason (lots of flux) and it works like a charm

 

[carlinb17]

Another suggestion is start probing, use an audio probe at the start of your signal and follow it though the circuit. If you hit a point where it stops, goes wonky, or isn’t right then you go to the previous component and start trouble shooting from there.

 

[Andyisdumb]

Another suggestion is start probing, use an audio probe at the start of your signal and follow it though the circuit. If you hit a point where it stops, goes wonky, or isn’t right then you go to the previous component and start trouble shooting from there.

Update: I think it was the Q2 transistor, because when I touched it with my finger, the noise stopped, so I re flowed all the joints, no more feedback but now no sound at all, changed foot switch, still no dice

 

[carlinb17]

Are your cables connected correctly, when the circuit is upside down the output is on the left and input is on the right, it will work on bypass backwards but not when activated. I’ve fallen victim to this before. Also if you continue to follow the audio probe through the circuit you can see where the sound stops.

 

[Andyisdumb]

Are your cables connected correctly, when the circuit is upside down the output is on the left and input is on the right, it will work on bypass backwards but not when activated. I’ve fallen victim to this before. Also if you continue to follow the audio probe through the circuit you can see where the sound stops.

I will have to build an audio probe and do that. The connections were definitely correct, I’ll have to learn how to read schematics and trace it on the board haha I’m very new to this

 

[fig]

Here you go;

You’ll only get audio from one side of those resistors/caps going to Vcc and GND.

 

[carlinb17]

Here you go;

You’ll only get audio from one side of those resistors/caps going to Vcc and GND.

Fig in for the kill!

 

[fig]

After last night, I felt a real need to offer something potentially useful